5070_s03_qp_2
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SP (SM/SLC) S34847/2© CIE 2003 [Turn over
CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Ordinary Level
CHEMISTRY 5070/02
Paper 2 TheoryMay/June 2003
1 hour 30 minutesCandidates answer on the Question Paper.Additional Materials: Answer Paper
READ THESE INSTRUCTIONS FIRST
Write your name, Centre number and candidate number in the spaces at the top of this page and on anyseparate answer paper used.
Sections AAnswer all questions.Write your answers in the spaces provided on the question paper.
Section BAnswer any three questions.Write your answers on the separate answer paper.At the end of the examination, fasten any separate answer paper used securely to the question paper.
The number of marks is given in brackets [ ] at the end of each question or part question.A copy of the Periodic Table is printed on page 16.
Centre Number Candidate Number Name
If you have been given a label, look at thedetails. If any details are incorrect ormissing, please fill in your correct detailsin the space given at the top of this page.
Stick your personal label here, ifprovided.
For Examiner’s Use
Section A
B8
B9
B10
B11
TOTAL
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5070/02/M/J/03
Section A
Answer all the questions in this section in the spaces provided.
A1 Choose from the following elements to answer the questions below.
argon bromine carbon hydrogen
iodine iron neon sulphur
Each element can be use used once, more than once, or not at all.
Name an element which
(a) forms a basic oxide,
......................................................................................................................................[1]
(b) is a liquid at room temperature and pressure,
......................................................................................................................................[1]
(c) reacts with aqueous copper(II) sulphate to give a pink solid,
......................................................................................................................................[1]
(d) is formed during the electrolysis of concentrated aqueous sodium chloride,
......................................................................................................................................[1]
(e) has a giant molecular structure.
......................................................................................................................................[1]
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A2 Ethanol, CH3CH2OH, is a liquid fuel. Ethanol can be manufactured either from glucose,C6H12O6, or from ethene.
(a) Briefly describe the manufacture of ethanol from glucose.Include the balanced equation in your answer.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
......................................................................................................................................[4]
(b) (i) Draw the displayed formula for ethene.
(ii) Name the substance that reacts with ethene to make ethanol.
...................................................................................................................................
(iii) Give the conditions needed for this reaction.
...................................................................................................................................
...................................................................................................................................[4]
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5070/02/M/J/03
A3 Petroleum is a complex mixture of hydrocarbons. Petroleum is a source of many useful fuels.
(a) What is meant by the term hydrocarbon?
..........................................................................................................................................
......................................................................................................................................[1]
(b) Petroleum is separated by fractional distillation.
(i) Complete the following table about the fractions obtained from petroleum.
(ii) Name one other fraction obtained from petroleum.
...................................................................................................................................[3]
(c) Fractional distillation of petroleum does not produce sufficient of some fractions tomatch demand.Cracking is used to convert large hydrocarbon molecules into smaller molecules thatare more in demand.
A hydrocarbon of molecular formula C12H26 is cracked.
(i) Suggest the formula of one alkane that may be produced.
...................................................................................................................................
(ii) Suggest the formula of one alkene that may be produced.
...................................................................................................................................
(iii) Describe a chemical test that can be used to distinguish between an alkene and analkane.
chemical test .............................................................................................................
result with alkane ......................................................................................................
result with alkene ......................................................................................................[4]
ForExaminer’s
Use
fraction
petrol (gasoline)
paraffin (kerosene)
diesel
bitumen
use
fuel for cars
fuel for diesel engines
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5070/02/M/J/03 [Turn over
A4 Carbon dioxide is a greenhouse gas. Carbon dioxide is given a greenhouse factor of 1. Othergases are given a greenhouse factor that compares their effect with carbon dioxide. Thegreenhouse effect increases as the factor value increases. The table gives some informationabout four different gases.
(a) State one possible consequence of an increased greenhouse effect.
......................................................................................................................................[1]
(b) Give one source of methane.
......................................................................................................................................[1]
(c) Why is an increase in the percentage of methane more worrying than the samepercentage increase of carbon dioxide?
..........................................................................................................................................
......................................................................................................................................[1]
(d) What other environmental problem, beside its action as a greenhouse gas, is caused byCCl3F?
......................................................................................................................................[1]
ForExaminer’s
Use
gas
CO2
CH4
N2O
CCl3F
greenhousefactor
1
30
160
21000
percentage of gasin the atmosphere
0.036
0.0017
3.0 � 10–4
2.8 � 10–8
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A5 Marble statues are being damaged by acid rain. The chemical name for marble is calciumcarbonate.
A student investigated the reaction between marble chips and nitric acid.
CaCO3(s) + 2HNO3(aq) → Ca(NO3)2(aq) + H2O(l) + CO2(g)
The diagram shows the apparatus the student used.
The student recorded the balance reading every minute.
The table shows the results.
(a) Explain why the balance reading decreases during the experiment.
..........................................................................................................................................
......................................................................................................................................[1]
(b) How can the student tell when the reaction has finished?
..........................................................................................................................................
......................................................................................................................................[1]
93.30g
50cm3 of 2.0mol/dm3
nitric acid2.0g marble chips
ForExaminer’s
Use
time / minutes
0123456789
1011121314
balance reading / g
93.3093.2893.2693.2493.2293.2193.2093.1993.1893.1793.1693.1593.1593.1493.14
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(c) (i) Calculate the number of moles of nitric acid in 50 cm3 of 2.0 mol / dm3 solution.
(ii) Calculate the number of moles of calcium carbonate in 2.0 g.
(iii) Which reagent, calcium carbonate or nitric acid, is in excess?Explain your answer.
[5]
(d) The student repeats the experiment using the same quantities of calcium carbonate andnitric acid. This time the acid is at a higher temperature. Describe and explain, in termsof collisions between reacting particles, the effect of increasing the temperature on therate of reaction.
..........................................................................................................................................
..........................................................................................................................................
......................................................................................................................................[2]
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A6 A student adds aqueous sodium hydroxide from a burette into 25.0 cm3 of dilute sulphuricacid. The student measures the pH value of the mixture during the addition of the sodiumhydroxide.
(a) Describe how the pH value changes.
......................................................................................................................................[1]
(b) Give an ionic equation to represent the neutralisation reaction between sodiumhydroxide and sulphuric acid.
......................................................................................................................................[1]
(c) Sulphuric acid is a strong acid.
(i) What is meant by the term acid?
...................................................................................................................................
...................................................................................................................................
(ii) What is the difference between a strong acid and a weak acid?
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................[3]
(d) Dilute sulphuric acid reacts with magnesium to give hydrogen.Give the ionic equation for this reaction.
......................................................................................................................................[1]
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A7 The structures of two ionic lattices are shown below.
(a) Explain why these two solids do not conduct electricity.
..........................................................................................................................................
......................................................................................................................................[1]
(b) (i) Explain why magnesium oxide has a very high melting point.
...................................................................................................................................
...................................................................................................................................
(ii) Suggest why the melting point of magnesium oxide is much higher than that ofsodium chloride.
...................................................................................................................................
...................................................................................................................................
...................................................................................................................................[2]
(c) Draw the electronic structure of a magnesium ion and of an oxide ion.
magnesium ion
oxide ion
[2]
Mg2+ O2–
O2–
Mg2+
Mg2+
O2–
O2– Mg2+
Na+ Cl –
Cl –
Na+
Na+
Cl –
Cl – Na+
magnesium oxide sodium chloride
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5070/02/M/J/03
Section B
Answer three questions from this section.
B8 The NASA space shuttle uses fuel cells to generate electricity. The diagram below shows ahydrogen-oxygen fuel cell.
At the positive electrode, oxygen reacts with water as shown.
O2(g) + 2H2O(l) + 4e– → 4OH–(aq)
At the negative electrode, hydrogen reacts with hydroxide ions as shown.
H2(g) + 2OH–(aq) → 2H2O(l) + 2e–
The overall reaction in the fuel cell is the reaction between hydrogen and oxygen to make water.
(a) Give one source for hydrogen and one source for oxygen for use in a fuel cell. [2]
(b) What is the name of the electrolyte used in the fuel cell? [1]
(c) What type of reaction takes place, reduction or oxidation, at the positive electrode? Explainyour answer. [1]
(d) A fuel cell uses 240 dm3 of hydrogen. Calculate the volume of oxygen needed, and the massof water formed. All gas volumes measured at room temperature and pressure. [3]
(e) Describe some advantages and disadvantages of using a fuel cell to generate electricity. [3]
external circuit
hydrogen in oxygen in
water
negative electrode positive electrode
electrolyteNa+ (aq)
OH– (aq)
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B9 The table gives information about the first five members of the homologous series of carboxylicacids.
(a) (i) Predict the formula and the relative molecular mass for pentanoic acid.
(ii) Explain why it is easier to predict the boiling point of pentanoic acid than the meltingpoint.
[3]
(b) Draw the displayed formula for propanoic acid. [1]
(c) Analysis of an organic acid isolated from red ants shows that it contains 0.060 g of carbon,0.010g of hydrogen and 0.16 g of oxygen.Calculate the empirical formula for this acid. [2]
(d) Ethanoic acid reacts with magnesium oxide.Name the products formed and write a balanced equation for the reaction. [2]
(e) Describe how ethanoic acid can be converted into ethyl ethanoate. [2]
name of acid
methanoic acid
ethanoic acid
propanoic acid
butanoic acid
pentanoic acid
formula
HCO2H
CH3CO2H
C2H5CO2H
C3H7CO2H
relativemolecular mass
46
60
74
88
melting point / °C
8.4
17
–22
–8
boiling point / °C
101
118
141
164
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B10 Methane, CH4, is used as a fuel. The complete combustion of methane can be represented by theequation below.
(a) Explain why this reaction is exothermic in terms of the energy changes that take place duringbond breaking and bond making. [3]
(b) Calculate the energy released when 4.0 g of methane is completely combusted. [2]
(c) Draw the energy profile diagram for the complete combustion of methane.Label on the diagram the activation energy and the enthalpy change. [3]
(d) Draw a ‘dot and cross’ diagram to show the bonding in methane.You only need to draw the outer (valence) electrons of carbon. [2]
H
CH H + 2 O + 2O CO O
H H
O
H∆H = –890kJ/mol
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B11 Coal-burning power stations produce sulphur dioxide and oxides of nitrogen.These two gases cause acid rain.
(a) Nitric oxide, NO, is made in a power station when nitrogen and oxygen react together.Write the equation for this reaction. [1]
(b) Many coal burning power stations are now fitted with a flue gas desulphurisation plant whichremoves sulphur dioxide and nitrogen dioxide from the gaseous emissions.
In a flue gas desulphurisation plant, powdered calcium carbonate reacts with sulphur dioxideas shown.
SO2(g) + CaCO3(s) → CaSO3(s) + CO2(g)
(i) Suggest why the calcium carbonate is powdered. [1]
(ii) Calculate the mass of calcium carbonate needed to react with 8000 kg of sulphurdioxide. [3]
(iii) Nitrogen dioxide also reacts with calcium carbonate. Suggest the name of the solidproduct of this reaction. [1]
(c) In the air sulphur dioxide reacts with nitrogen dioxide forming sulphur trioxide. The reactionsthat take place are shown in the equations.
SO2 + NO2 → SO3 + NO
2NO + O2 → 2NO2
Suggest the role of nitrogen dioxide in these reactions. Explain your answer. [2]
(d) Sulphur dioxide is used in the Contact process to make sulphuric acid.Describe the conditions and name the catalyst in the Contact process. [2]
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5070/02/M/J/03
Gro
up
DA
TA S
HE
ET
Th
e P
erio
dic
Tab
le o
f th
e E
lem
ents
140
Ce
Cer
ium
58
141
Pr
Pra
seod
ymiu
m
59
144
Nd
Neo
dym
ium
60
Pm
Pro
met
hium
61
150
Sm
Sa
ma
riu
m
62
152
Eu
Eur
opiu
m
63
157
Gd
Gad
olin
ium
64
159
Tb
Terb
ium
65
162
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m
67
167
Er
Erb
ium
68
169
Tm
Thu
lium
69
173
Yb
Ytte
rbiu
m
70
175
Lu
Lute
tium
71
232
Th
Tho
rium
90
Pa
Pro
tact
iniu
m
91
238 U
Ura
nium
92
Np
Nep
tuni
um
93
Pu
Plu
toni
um
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m
97
Cf
Cal
iforn
ium
98
Es
Ein
stei
nium
99
Fm
Fer
miu
m
100
Md
Men
dele
vium
101
No
Nob
eliu
m
102
Lr
Law
renc
ium
103
1 HH
ydro
gen
1
7 Li
Lith
ium
3
23 Na
Sod
ium
11
24 Mg
Mag
nesi
um
12
40 Ca
Cal
cium
20
45 Sc
Sca
ndiu
m
21
48 Ti
Tita
nium
22
51 VV
anad
ium
23
52 Cr
Chr
omiu
m
24
55 Mn
Man
gane
se
25
56 Fe
Iron
26
59 Co
Cob
alt
27
59 Ni
Nic
kel
28
64 Cu
Cop
per
29
65 Zn
Zin
c
30
70 Ga
Gal
lium
31
27 Al
Alu
min
ium
13
11 BB
oron
5
12 CC
arbo
n
6
14 NN
itrog
en
7
16 OO
xyge
n
8
19 FF
luor
ine
9
28 Si
Sili
con
14
31 PP
hosp
horu
s
15
32 SS
ulph
ur16
35.5
Cl
Chl
orin
e17
40 Ar
Arg
on18
20 Ne
Neo
n10
4 He
Hel
ium
2
73 Ge
Ger
man
ium
32
75 As
Ars
enic
33
79 Se
Sel
eniu
m
34
80 Br
Bro
min
e
35
84 Kr
Kry
pton
36
39 KP
otas
sium
19
88 Sr
Str
ontiu
m
38
89 YY
ttriu
m
39
91 Zr
Zirc
oniu
m
40
93 Nb
Nio
bium
41
96 Mo
Mol
ybde
num
42
Tc
Tech
netiu
m
43
101
Ru
Rut
heni
um
44
103
Rh
Rho
dium
45
106
Pd
Pal
ladi
um
46
108
Ag
Silv
er
47
112
Cd
Cad
miu
m
48
115
In Indi
um
49
119
Sn
Tin
50
122
Sb
Ant
imon
y
51
128
TeTe
lluriu
m
52
127 I
Iodi
ne
53
131
Xe
Xen
on
54
137
Ba
Bar
ium
56
139
La
Lant
hanu
m
57*
178
Hf
Haf
nium
72
181
TaTa
ntal
um
73
184
WTu
ngst
en
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192 Ir
Irid
ium
77
195
Pt
Pla
tinum
78
197
Au
Gol
d
79
201
Hg
Mer
cury
80
204
Tl
Tha
llium
81
207
Pb
Lead
82
209
Bi
Bis
mut
h
83
Po
Pol
oniu
m
84
At
Ast
atin
e
85
Rn
Rad
on
86
Fr
Fran
cium
87
227
Ac
Act
iniu
m
89
†
9 Be
Ber
ylliu
m
4
III
IIIIV
VV
IV
II0
85 Rb
Rub
idiu
m
37
133
Cs
Cae
sium
55
226
Ra
Rad
ium
88
The
vol
ume
of o
ne m
ole
of a
ny g
as is
24
dm3
at r
oom
tem
pera
ture
and
pre
ssur
e (r
.t.p.
).
a Xb
a =
rel
ativ
e at
omic
mas
s
X=
ato
mic
sym
bol
b =
pro
ton
(ato
mic
) nu
mbe
r
Key
* 58-
71 L
anth
anoi
d se
ries
†90-
103
Act
inoi
d se
ries
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